Micellar desorption of polynuclear aromatic hydrocarbons from contaminatedsoil

Efficacious application of in situ surfactant-aided biodegradation for poly nuclear aromatic hydrocarbon (PAH) compounds requires a sound understanding of the behavior of surfactants in these systems. We investigated the desor ption of PAH compounds from an aged soil at a former manufactured gas plant site with Alfonic 1412-7, a nonionic alkyl ethoxylate surfactant. When con centrations of Alfonic were lower than twice the critical micelle concentra tion, PAH desorption was negligible. This was attributed to the sorption of the surfactant to the soil. At higher concentrations, Alfonic significantl y enhanced the extent and rate of release of PAH compounds from the soil im plying that mechanisms that increased matrix diffusivities in addition to m icellar sinks may be operational. Evidence for soil organic matter desorpti on was also demonstrated. (C) 2001 Elsevier Science B.V. All rights reserve d.